Sylvania



named m. a, 1931 UNITED STA ES PATENT OFFICE CONRAD H; ZIEBD'I, OI BOBDALE, PENN TOWNSHIP, ALLEGHm COUNTY, PENN- SYLVANIA, ASSIGNOB 1'0 rm: UNION SWITCH & SIGNAL GOIPANY, PENNSYLVANIA, A CORPORATION 01' PENNSYLVANIA or swIssvaLn,

VOLTAGE-BEGULATING APPARATUS Application filed October 18, 1928. Serial Io. 812,048.

My invention relates to voltage r lating apparatus, that is, apparatus for use tween a source of energy and an energy consuming device for regulating the voltage applied to said device.

I will describe several forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showing one form of voltage regulating apparatus embodying my 1n I vention applied to a storage battery charging circuit. Fig. 2 is a diagrammatic view showing one form of voltage regulating apparatus embodying my invention applied to a track circuit. Fig. 3 is a diagrammatic View showing another form of voltage regulating apparatus embodying my invention applied to a track circuit. Fig. 4 is a view showing still another form of voltage regulating apparatus embodying my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the referencecharacter T designates a transformer, the primary 14 of which is connected with a suitable source of alternating current here shown as an alter nator G. The secondary 15 of transformer T is connected, through a current limiting 1mpedance A, with the input terminals 7 and 7 of a rectifier R comprising a plurality of asymmetric units 9 connected in the usual manner to provide full wave rectification. The output terminals 8 and 8' of rectifier R are connected through a switch F with a storage battery C which is to be charged by the unidirectional current delivered by the rectlfier. I

With theapparatus constructed in the manner thus far described, under normal conditions, that is, when switch F is closed, cur-'- rent from the secondary 15 of transformer T is supplied to battery C through rectifier R,

and the parts are so proportioned that this current upon flowing through the mpedance A creates a potential drop in the impedance which maintains the voltage impressed across the input terminals 7 and 7" of rectifier R at a value which is slightly higher than the terminal voltage of storage battery 0. The 1m- .now, switch F is opened, the current flowing in impedance A is greatly diminished, so that the potential drop across the impedance is also greatly diminished, and if the voltage of the secondary 15 of transformer T is constant, the voltage im ressed across the input terminals of recti er R rises. This rise in voltage in some instances ma be sufliciently great to dama e the rectifier To prevent this undesira l'e rise in voltage, I provide a reactor B comprisin a closed iron core 6 carrying a primary winding 3 and a secondary winding 4. The terminals 12 and 13 of the primary winding 3 of reactor B are connected with the input terminals 7 and 7 respectively of rectifier B. An asymmetric unit 5 is connected directly across the secondary Winding 4 of reactor B.

It is apparent that the Volta e impressed across input terminals 7 and g of rectifier R is also impressed across terminals 12 and 13 of winding 3 of reactor B.- An alternating current therefore flows in winding 3, and an alternating flux is set up in core 6. This alternating flux in core 6 tends to induce an alternating electromotive force in winding 4 of reactor B, but since asymmetric unit 5 is connected in series with winding 4, a unidirectional current flows in winding 4 which creates a unidirectional flux in core 6 in addition to the alternating flux created in core 6 by the alternating current in winding 3. The parts of reactor B are so proportioned that under normal conditions, that is, when switch F is closed, the flux density in the core 6 is near saturation. If, now, the voltage impressed upon rectifier R tends to rise for any reason, such as the opening of switch F, the current flowing in winding 3 of reactor B increases, so that the flux density in core 6 increases, and the impedance of winding 3 therefore decreases. Since winding 4 and rectifier 5 co-operate to create a unidirectional flux in core 6, as has already been described, the decrease in imer than we be the case if winding 4 and rectifier 5 were omitted. As a result of this decrease in the impedance of winding 3, the current through the winding is stil further increased. ut the increased current in winding 3 causes an increase in the tential drofiflacross impedance A, with the al result t t the voltage applied to terminals 7 and 7" of rectifier B when switch F is oplened is considerabl smaller than would t e case1 ifi reactor hwere not; rovdtelmli. pro r y esigning t e reactor an e ini pedaifize A, the voltage across the terminals of rectifier B may be made substantially constant.

Referring now to Fig. 2, the reference characters 1 and 1" designate the track rails of a stretch of railway track over which traflic normally moves in the direction indicated by the arrow. These rails are divided, by means of insulated 'oints 2, to form a track section D-E. T c section D-E is' provided with a source of track circuit current, here shown as a track transformer H having its secondary 11 connected across the rails adjacent the exit end of the section. Inte sed between the rail 1 of section D- and the secondary 11 of track transformer H is an impedance A, one function of which is to limit the output of the transformer when its terminals are short circuited by the wheels and axles of a train. The primary 10 of transformer H is constantly supplied with alternating current from a suitable source, here shown as an alternator G. Section DE is also provided with a track relay L which is connected across the rails adjacent theentrancc end of the section.

It is clear that there will be a certain amount of current leakage between the rails 1 and 1, and that the amount of this leakage will depend upon the resistance of the track ballast which varies with weather conditions, etc. Since the volta e at the secondary 11 of transformer T is constant, it

follows that with only the apparatus thus.

far described, the voltage applied to the terminals of relay L would vary in response to chan in ballast resistance. This variation in v0 tags is undesirable, and to prevent its occurrence, I connect across the terminals of relay L, the terminals 12 and 13 of the winding 3 of the reactor B shown in Fig. 1, and I so design the reactor that when normal voltage is impressed across the terminals of relay L, the core 6 of reactor B is nearly saturated by the alternating and the unidirectional fluxes in the core.

The parts in Fig. 2 are further proportioned in such manner that under the worst conditions, that is, when leakage from rail to rail is maximum, the voltage impressed across the terminals of relay L is suflicient to ing 3 of reactor B also tends to increase, and

the current flowing in windin 3 increases for reasons previously pointe out m connection with Fig. 1. When the current in winding 3 increases, however, the potential drop in the rails and in impedance'A also increases, and by properly designing reactor B, the voltage at the terminals of relay L can be held substantially constant.

Referring now to Fig. 3, the apparatus shown in this view is the same as that shown.

in Fi 2, except that the reactor B is replace by a reactor J in which winding 4 is omitted. This is made possible by tapping the winding 3 at an intermediate point 16 and by connecting an asymmetric unit 17 between this point and one end of the winding. External connections are then made to the reactor between the point 16 and the other end of the winding 3. The parts of reactor J are so proportioned, that when normal voltage is impressed across terminals 12 and 13, the alternatin current which flows in the lower half 0 winding 3 and the unidirectional current which flows in the upper-half of winding 3 ,magnetize the core 6 to a flux density which is near saturation. The reactor J may also be substituted for reactor B in the combination shown in Fig. 1.

In the reactor K shown in Fig. 4, an asymmetric unit 18 is connected in series with the winding 3 so that the current flowing in windin 3 is unidirectional current. The reactor is so designed that when normal volta e is impressed across terminals 12' and 13 o winding 3, the flux density in core 6 is near saturation. I have found that with the reactor constructed in this manner, since the flux in core 6 is a unidirectional flux, the decrease in impedance in winding 3 for a given rise in voltage at terminals 12 and 13 is considerably greater than the decrease in impedance in the winding of a similar reactor not having the asymmetric unit 5 in series with the winding. This effect may further be increased by using an asymmetric unit 18 of the type comprising a copper disk having a coating of cuprous oxide formed on one portione the first portion of said win density in said core due to the current in bothportions of said is near saturation.

of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what and receiving current from said source, and

an asymmetric unit connected in series with the remaining portion of said winding for causing a unidirectional current to flow in said remaining portion, the arts of said reactor being so proportioned t at when normal voltage is im ressed across the first portion of said winding the flux density in said core due to the current in both portions of said winding is near saturation.

2. Voltage regulating apparatus comprising a reactor having an iron core provided with a winding, and an asymmetric unit connected in series with a portion of said winding, the arts of said reactor being so prod 'that when normal voltage is impressed across the remaining portion of said winding the flux density of said core due to the current in both portions ofsaid winding is near saturation.

3. In combination, a stretch of railway track, a source of alternating current connected with the rails of said stretch, animpedance interposed between said source and a track rail, a relay connected with the rails of said stretch, an iron core reactor a portion of its winding connected in multiple with said relay, and an asymmetric unit connected in series with the remaining portion of said windingfor causing a unidirectional current to flow in said remaining portion, the

parts of said reactor being so proportioned that when normal voltage 1s g e v ux 

